Tandem and colpostat, and tandem and ring applicators are each used for treating cervical and uterine cancer with high-dose-rate (HDR) brachytherapy, a process for delivering high-intensity radiation directly into tumor sites. The tandem and colpostats/ring are placed near the tumor and radiation therapy is given through the applicator by placing a radioactive source at multiple positions inside the hollow portions of the applicator. Worldwide, each year more than 600,000 women develop some form of gynecological cancer.
At least some known brachytherapy techniques use image guided brachytherapy (IGBT) that includes cross sectional image data to create 3D models of the anatomical structures. For example, known image guided brachytherapy include computed tomography (CT) and magnetic resonance imaging (MRI) systems. These systems are used for checking applicator placement and brachytherapy dose planning. The precise placement of the applicator is important for the radiotherapy to be optimally targeted to the tumor.
Imaging for gynecological brachytherapy is slowly evolving from planar x-rays to CT to MR volumetric imaging for improved visualization of the patient normal anatomy and disease. At least some known tandem and colpostat/ring applicators are made of titanium so that that they are stable and do not bend, deform, or move within the patient. When these titanium tandems are used with MRI, artifacts are created which cause a distortion of the boundaries of the applicator, which in turn hinders the ability to define the exact localization of the tandem in proximity to the tumor and in turn to optimally target the radiotherapy to the tumor.